Oxycirrhites typus aka the longnose hawkfish is a reef aquarium favourite. What’s not to love about this fish, with its red and white checkered patterning, elongated mouth and prominent dorsal fin?

In the wild, the longnose hawkfish can be found haunting the reefs of the Indian and Pacific oceans, where it can grow to be 5 inches and live 5 to 7 years.This fish lacks a swim bladder, so instead of floating in the water it prefers to sit on corals, resting on its pectoral fins, waiting patiently for passing prey. When the opportunity arises, the longnose hawkfish will burst forward and ambush its prey, much like a hawk swooping down from a perch, thus the common name for the family (Cirrhitidae) of fish that the longnose belongs to. The prefered prey of Longnose Hawkfishes are small crustaceans and invertebrates, including copepods.

All longnose hawkfish start their lives as a female, with the largest individual in a territory changing sex to male, which is called sequential hermaphroditism. This large male will then monopolize mating with the nearby females in his home range, which makes changing sex from female to male advantageous for the species. While small females have no difficulty spawning, small males do. This system ensures that individuals are able to achieve maximum reproductive success throughout their lives.

Before sunset, the male longnose hawkfish in a territory will begin courtship with a female by swimming to her coral with dorsal fin erect. Courtship behaviour consists of the male and female circling each other among the coral with short periods of rest where they rest next to each other on the coral. As courtship progresses the male will follow the female as she leads him in short movements through the coral branches and during rests the male will begin to nudge the female with his snout. The male then often mounts the female, resting his pectoral fins on her while vigorously beating his tail. Just before spawning, the pair will align themselves parallel to each other, point themselves upwards with dorsal fins  and fin spines raised, and quickly swim up away from the coral. At their apex, they turn their snouts downward and rapidly flex their bodies, releasing a cloud a eggs and sperm, and return to the coral. The male then visits the other females in his territory to continue courtship and spawning behaviour.

In the aquarium, unless you have a very large one, it’s a good idea to have only one hawkfish, as they can be rather territorial with each other, inter and intraspecifically. It’s also a good idea to keep an eye on any small inverts in your tank, as longnose hawkfish are known to eat or bully snails and shrimp.

References

Donaldson, T.J., Colin, P.L., 1989. Pelagic spawning of the hawkfish Oxycirrhites typus (Cirrhitidae). Environmental Biology of Fishes. 24(4):295-300

Donaldson, T.J., 1990. Reproductive Behavior and Social Organization of Some Pacific Hawkfishes (Cirrihitidae). Japanese Journal of Ichthyology. 36(4):439-458

Larson, E.T., 2011. Neuroendocrine Regulation in Sex-changing Fishes. Hormones and Reproduction of Vertebrates. 8:149-168